So driving to work today my car started misfiring really bad randomly and the car sounded like it was under water, the battery light blinked then stopped quickly after and the check engine light blinked as i pulled over and turned the car off. i turned it back on and it was fine. the past few days my car has sounded like a spark plug backed out, a little popping hiccupy noise in the idle and in mid RPM's driving around town, so i checked the plugs earlier today and tightened them a little bit. i don't get what it could be unless the 2 new napa brand coils i bought are bad? then a second time during my 10 minute drive to work, it misfired again, no blinking lights, then randomly just went to idle from a stop and fixed itself and ran fine. then driving back home after about 5 minutes it did it a third time and once again it just went away. how the hell do i fix this and what could it be?